The present invention emanates from a method and a device for the detection of corrosion in an at least partially electrically conductive housing of an electric energy storage unit as well as an electric energy storage system.
In many applications, e.g. in the automobile field, battery cells, which are based on lithium-ion technology, have a metallic housing. This provides mechanical stability and prevents liquids from entering into electrically sensitive areas. This is especially important in the automotive field where safety requirements are high and must not be compromised as lives could be at stake. However, under certain conditions, the metallic housing is prone to electrochemical reactions which may occur inside the cell, for example in areas of the housing which are in contact with an electrolyte. Electric potential gradients within a battery cell may enable these reactions which can lead to corrosion from the inside of the battery cell. Finally, this may even cause leakage of the battery cell. It is therefore essential to detect a possible corrosion problem early in its development to be able to carry out necessary measures.
The document DE 3904894 C1 describes a method and a device for the determination of corrosion on components. To this end, an electrically conductive measuring wire is installed alongside the component which is monitored for corrosion. The electrically conductive measuring wire is hence also exposed to a possibly corrosive environment. By analyzing the electrical resistance of the measuring wire, corrosion can be detected and analyzed.